This invention relates to a technology of collecting statistics of an amount of data transferred to a network and pieces of alarm information from an access terminal for housing a user terminal installed at a remote place.
Carriers that provide guarantee type communication services in place of conventional dedicated-line services by using a packet transfer network have increased. The guarantee type communication services are services in which carriers install access terminals at user sites, and the carriers guarantee contracted communication bandwidths between the access terminals.
A representative example of the packet transfer network is the Internet. The Internet is a service based on best effort. Thus, there is a fear that data may be discarded in the middle of a path. However, how much and where data is discarded does not have to be figured out.
On the other hand, in the service that guarantees a contracted communication bandwidth, when data transmitted from the user terminal abiding by the guaranteed bandwidth is discarded in the packet transfer network provided by the carrier, it is violation of a contract, and the carrier accordingly has to pay a penalty.
A network for interconnecting the user sites may be configured not by a single network but by a plurality of networks such as an access network and a transport network. The plurality of networks may be administered by different administration companies.
Thus, when data is discarded or when a communication failure occurs, a failure occurring in the network including the access terminal, or a place where data has been discarded has to be specified to clarify a locus of responsibility.
The transport network includes an edge node and a transport node for interconnecting an access network and the transport network. In the transport network, a control network for setting control information may be coupled to the nodes. An administrator of the transport network can monitor statistical information of data passing through the transport node or information of a failure occurring in the transport node by means of the control network.
One of communication protocols for constructing the transport network is ATM. In the ATM, operation administration and maintenance (OAM) is defined. The OAM of the ATM includes failure notification from the transport node, and collection of pieces of statistical information limited within an application range of the OAM.